Step 08: i materiali (parte 1)

Materiali del pendolo dell'apparato tripendolare

"The bob, stem, and the head of a pendulum are made from one piece of nickel-steel. There is not joint. The knife-edge is made of stellite, an extremely hard ad incorrodible substance made of chronium and cobalt, with the admixture of a small quantity of molybdenum."

(The Geographical Journal, Vol. 73, No. 4 (Apr., 1929), pp. 330, published by: The Royal Geographical Society)